This application relates to a scroll compressor wherein the flow of returned economized fluid into the compression chambers occurs through greater port area than has been the case in the prior art.
Scroll compressors are becoming widely utilized in refrigerant compression applications. As known, in a scroll compressor, two scroll members each have a base and a generally spiral wrap extending from the base. The wraps interfit to define a pair of compression chambers. One of the two scroll members is caused to orbit relative to the other, and as the scroll member orbits, the size of the compression chambers reduces, compressing an entrapped refrigerant.
One feature that is becoming more common in refrigerant cycles is the use of an economizer cycle. In an economizer cycle, a refrigerant is tapped downstream of a heat exchanger, and caused to flow through a separate economizer expansion device, and then through an economizer heat exchanger. In the economizer heat exchanger, this tapped refrigerant subcools a main refrigerant flow, providing a greater cooling capacity from the main refrigerant flow.
The refrigerant from the tap is returned to the compressor at an intermediate compression point. In scroll compressors, it is often the case that this returned economizer flow flows through the base of the fixed or orbiting scroll, and into the compression chambers.
Known scroll compressors have typically utilized two injection ports returning the refrigerant into the pair of chambers with one of each of the ports communicating with one of each of the pair of chambers exclusively. However, some known compressors have utilized a single port which communicates alternately between each of the pair of chambers as the tip of the wrap of the mating scroll moves over it. The size of a single port has generally been limited in cross-sectional area to prevent the flow of refrigerant from one of the chambers to the other through the port. That is, it has been seen as desirable to the scroll compressor designer that this port have a diameter that is at most only slightly larger than the width of the scroll wrap, such that the scroll wrap will prevent the flow from one of the chambers to the other as the wrap moves over the port. Known scroll compressors have used a single port whose diameter is up to about 1.5 times the width of the scroll wrap. This has limited the cross-sectional area of the hole, and limited the amount of refrigerant that can be returned through the economizer injection port.